How does electronic ballast start 2 pin 13 watt PLS...?

[JohnR66]

.... Without triggering the glow switch starter?

I have a 13 watt utility lamp w/ electronic ballast. When I turn it on, the
lamp lamp lights instantly without the flickering start. It is instant on as
if turning on an incandescent lamp. I'm not sure how it it fires the lamp
with cold heaters without causing the glow switch to conduct first.
John

 

[Victor Roberts]

... Without triggering the glow switch starter?

I have a 13 watt utility lamp w/ electronic ballast. When I turn it on, the
lamp lamp lights instantly without the flickering start. It is instant on as
if turning on an incandescent lamp. I'm not sure how it it fires the lamp
with cold heaters without causing the glow switch to conduct first.
John

a) High voltage applied to the lamp while the electrodes are cold.
(Instant Start)

b) Ballast provides power to heat the electrodes and also provides a
high voltage to the discharge, but not as high as instant start.
(Rapid Start.)

--
Vic Roberts
http://www.RobertsResearchInc.com
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[Jeff Waymouth]

At least one company manufactures a 2 pin 13W compact fluorescent single
U tube lamp designed to do just that. It is built with a chip in th
base to create an instant start even though it is only a 2 pin lamp and
one would normally expect flickering from the glow bottle starter inside
the standard lamp. It is a seperate product and both are sold (chip and
glow bottle)

 

[Victor Roberts]

At least one company manufactures a 2 pin 13W compact fluorescent single
U tube lamp designed to do just that. It is built with a chip in th
base to create an instant start even though it is only a 2 pin lamp and
one would normally expect flickering from the glow bottle starter inside
the standard lamp. It is a seperate product and both are sold (chip and
glow bottle)

I didn't know about this 2-pin lamp, but assume the chip replaces the
starter and performs the same functions, so I would classify it as a
pre-heat lamp with an electronic starter.

I guess it is possible that the chip does not cause heating current to
flow through the electrodes, but just places a short across the output
of the ballast inductor so that a high voltage spike is generated when
the semiconductor switch opens - in that case I would have to call it
instant start, but I do not believe the short voltage pulse generated
this way would reliably start a lamp with cold electrodes.

--
Vic Roberts
http://www.RobertsResearchInc.com
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[Fritz Schlunder]

... Without triggering the glow switch starter?

I have a 13 watt utility lamp w/ electronic ballast. When I turn it on, the
lamp lamp lights instantly without the flickering start. It is instant on as
if turning on an incandescent lamp. I'm not sure how it it fires the lamp
with cold heaters without causing the glow switch to conduct first.
John

Huh? I don't know what the other dudes in this thread are talking about,
but...

Since the lamp only has two pins and is electronically ballasted I see no
reason why there should be a glow starter switch at all. I assume you have
misidentified some other component on the device as a glow starter switch.

With only two pins on the lamp there are no filaments that can be preheated
before the lamp is started. The ballast must simply provide very high
voltage to initiate and sustain the arc. Further an electronic ballast
won't normally contain a large mains frequency inductor/high leakage
autotransformer/etc. for use by a glow starter. Electronic ballasts for
fluorescent lamps usually use an LC resonant circuit driven near resonance
to produce the high voltage needed for starting. Then once the lamp starts
the frequency is controlled so as to detune the resonant circuit somewhat to
provide a ballasting (current limiting and stabilizing) function. The
operating frequency is typically in the several tens of kilohertz range, so
in theory a two pin lamp could be started in under one millisecond. Of
course, a normal electronically ballasted lamp won't start this fast since
it takes one or more mains cycles to charge the input capacitors enough to
operate. Nevertheless the ballast can be designed to start fast enough to
appear instantaneous to any human.

 

[Victor Roberts]

Huh? I don't know what the other dudes in this thread are talking about,
but...

Since the lamp only has two pins and is electronically ballasted I see no
reason why there should be a glow starter switch at all. I assume you have
misidentified some other component on the device as a glow starter switch.

Almost all 2-pin CFLs have a glow switch inside the plastic base.

With only two pins on the lamp there are no filaments that can be preheated
before the lamp is started.

The lamp has two electrodes and four wire leads, one from each end of
each electrode, passing through the glass. Two of the wire leads are
connected to the internal glow switch and the other two are connected
to the two external pins.

The ballast must simply provide very high
voltage to initiate and sustain the arc.

Not necessarily. 2-pin CFLs with internal glow switches are not
supposed to be used on electronic ballasts.

Further an electronic ballast
won't normally contain a large mains frequency inductor/high leakage
autotransformer/etc. for use by a glow starter. Electronic ballasts for
fluorescent lamps usually use an LC resonant circuit driven near resonance
to produce the high voltage needed for starting. Then once the lamp starts
the frequency is controlled so as to detune the resonant circuit somewhat to
provide a ballasting (current limiting and stabilizing) function. The
operating frequency is typically in the several tens of kilohertz range, so
in theory a two pin lamp could be started in under one millisecond. Of
course, a normal electronically ballasted lamp won't start this fast since
it takes one or more mains cycles to charge the input capacitors enough to
operate. Nevertheless the ballast can be designed to start fast enough to
appear instantaneous to any human.

The starting time is usually limited by the time needed to heat the
electrodes, not the operating frequency. For the best life, the CFL
electrodes are typically heated for about 1 second. Of course, any CFL
without a glow starter can be instant started on either a magnetic or
electronic ballast with some loss of life.

--
Vic Roberts
http://www.RobertsResearchInc.com
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[Victor Roberts]

I too have such a screw base ballast where you can plug in a 2 pin PL-S
fluorescent lamp with integrated glow bottle switch. Examining the
starting behaviour of the lamp, I conclude that is an instant start
type.

If it has an internal glow switch it cannot be "instant start." The
high voltages used for instant start operating would trigger the glow
switch - and if the ballast is instant start, it does not need a glow
switch.

But you can plug in a CFL with integrated glow bottle switch. And the
question is: "... how it fires the lamp with cold heaters without
causing the glow switch to conduct first?"

They probably glow, but in a moderate controlled manner.

--
Vic Roberts
http://www.RobertsResearchInc.com
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